Communication method, and communications apparatus and system

ABSTRACT

Embodiments of the present disclosure provide a communication method, and a communications apparatus and system. User equipment can communicate with the network device by using a plurality of beams, the plurality of beams include a first beam and at least one second beam, the first beam is a serving beam used by the user equipment to listen to control information, and the second beam is a beam other than the serving beam. The method includes: determining, by the user equipment, that the serving beam is blocked; and obtaining, by the user equipment, a first message from the network device by using the first beam or the second beam. According to the method, the UE may determine that the serving beam is blocked, and further obtain the first message sent by the network device, thereby eliminating an adverse effect caused by the blocking of the serving beam. Correspondingly, the network device may also determine that the serving beam is blocked, and further send the first message, thereby eliminating an adverse effect caused by the blocking of the serving beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/105683, filed on Oct. 11, 2017, which claims priority toChinese Patent Application No. 201610895666.7, filed on Oct. 13, 2016.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present application relates to the field of wireless communicationstechnologies, and in particular, to a communication method, and acommunications apparatus and system.

BACKGROUND

Currently, with gradual saturation of a low frequency band (for example,below 6 GHz) of a wireless communications system and an increasingrequirement for high-speed and large-capacity communication, using ahigh frequency band (for example, above 6 GHz) for communication becomesa trend. In a high-frequency wireless communications field, due to afrequency increase, a path loss increases, and a cell coverage areadecreases. In this case, more network devices (such as base stations) ina same area need to be deployed to ensure coverage, significantlyincreasing network deployment costs. For avoiding an increase of thenetwork deployment costs, a beamforming technology may be used.Beamforming is a multi-antenna processing technology, and provides abeam gain by using a plurality of antennas to form a narrowercommunication beam, so as to compensate for an increased path loss tosome extent and ensure that a cell radius does not significantlydecrease relative to that in a low frequency.

In the beamforming technology, there are a plurality of beams in a cell,user equipment (UE) in the cell listens to only information sent on oneof the beams, and the information may include a broadcast message, anuplink and downlink scheduling message, and the like. The beam is aserving beam of the UE, and the serving beam is usually a beam withoptimal signal quality in all beams that the UE can receive. A verynarrow beam is usually used for obtaining a relatively large beam gain.To ensure continuous coverage in the cell, a plurality of narrow beamsneed to be used. In this way, when moving in the cell, the UE isconfronted with a beam switching problem, to be specific, after movingfrom one beam coverage area of the cell to another beam coverage area,the serving beam needs to be switched.

In the prior art, UE measures different downlink beams and feeds back ameasurement result to a base station, and the base station determines,based on the measurement result, whether a serving beam of the UE needsto be changed. If the serving beam of the UE needs to be changed, thebase station delivers a beam switching instruction by using the currentserving beam, so as to instruct the UE to start to listen to a signal ofanother beam at a next predetermined moment. In other words, the otherbeam is used as a next serving beam of the UE. In short, in the priorart, the base station initiates a beam switching process based on thebeam measurement result fed back by the UE.

However, due to different cell scenarios, channel quality of ahigh-frequency communication channel in some cells is greatly changed,and the channel quality often greatly falls. In addition, ahigh-frequency signal has poor scattering and diffraction capabilities,and a signal propagation path is mostly a direct or refraction path andis also easily affected by an obstacle. Consequently, the high-frequencychannel is more vulnerable for various reasons. Sometimes, a beamblocking phenomenon occurs. In this case, communication between the basestation and the UE is adversely affected.

SUMMARY

The present disclosure provides a communication method, and acommunications apparatus and system, to resolve a technical problem thatcommunication is adversely affected in a beam blocking state.

According to a first aspect of embodiments of the present disclosure, acommunication method is provided, where user equipment can communicatewith a network device by using a plurality of beams, the plurality ofbeams include a first beam and at least one second beam, the first beamis a serving beam used by the user equipment to listen to controlinformation, the second beam is a beam other than the serving beam, andthe method includes: determining, by the user equipment, that theserving beam is blocked; and obtaining, by the user equipment, a firstmessage from the network device by using the first beam or the secondbeam.

With reference to the first aspect, in a first optional embodiment ofthe first aspect, the method further includes: sending, by the userequipment, a response message in response to the first message, wherethe response message is used to indicate a beam used by the userequipment to obtain the first message.

With reference to the first optional embodiment of the first aspect, ina second optional embodiment of the first aspect, the method furtherincludes: obtaining, by the user equipment, a beam switching messagethat is sent by the network device in response to the response message,where the beam switching message is used to indicate that one of theplurality of beams is a next serving beam of the user equipment.

With reference to the first aspect, in a third optional embodiment ofthe first aspect, the method further includes: sending, by the userequipment, a blocking message by using a preset uplink resource, wherethe blocking message is used to instruct the network device to send thefirst message in response to the blocking message.

With reference to the first, the second, or the third optionalembodiment of the first aspect, in a fourth optional embodiment of thefirst aspect, the second beam includes a plurality of beams.

With reference to the fourth optional embodiment of the first aspect, ina fifth optional embodiment of the first aspect, the obtaining, by theuser equipment, a first message from the network device by using thefirst beam or the second beam includes: receiving, by the user equipmenton the first beam and each second beam, the first message sent by thenetwork device; or

searching, by the user equipment, for all beams in a preset beamcombination, where the preset beam combination includes the first beam,or the first beam and any quantity of second beams; and receiving thefirst message that is sent by the network device by using any one ormore beams in the preset beam combination; or

selecting, by the user equipment at different time points by using apreconfigured correspondence between a beam and a time point, acorresponding single beam from the first beam and all second beams forperforming a search; and receiving the first message that is sent by thenetwork device by using the selected single beam; or

searching, by the user equipment, for all the beams in the preset beamcombination; when the first message is received on none of the beams inthe preset beam combination, selecting, at different time points byusing a preconfigured correspondence between a beam and a time point, acorresponding single beam from the plurality of beams or a beam outsidethe preset beam combination for performing a search; and receiving thefirst message that is sent by the network device by using the selectedsingle beam.

With reference to the first optional embodiment of the first aspect, ina sixth optional embodiment of the first aspect, the first messagecarries one piece or a combination of indication information and datainformation.

With reference to the sixth optional embodiment of the first aspect, ina seventh optional embodiment of the first aspect, the indicationinformation is a PDCCH order; the method further includes: in responseto the PDCCH order, generating, by the user equipment, a preamble; andthe sending, by the user equipment, a response message in response tothe first message includes: sending, by the user equipment, the preambleon a preset random access resource in a beam used by the first message;or

sending, by the user equipment, the preamble on a preset random accessresource in all beams used by the first message; or

determining, by the user equipment, a beam with a greatest communicationquality value in all beams used by the first message, and sending thepreamble on a preset random access resource in the determined beam; or

after sending the preamble on a preset random access resource in a beamon which the first message is received, receiving, by the userequipment, the first message from another beam, and if a communicationquality value of the another beam is greater than a communicationquality value of the previous beam, sending the preamble on a presetrandom access resource in the another beam.

With reference to the sixth optional embodiment of the first aspect, inan eighth optional embodiment of the first aspect, the indicationinformation is uplink scheduling indication information; the methodfurther includes: determining, by the user equipment, a measurementreport that includes communication quality of all beams; and thesending, by the user equipment, a response message in response to thefirst message includes: sending, by the user equipment, the measurementreport by using a preset time-frequency resource in any beam used by thefirst message.

With reference to the second optional embodiment of the first aspect, ina ninth optional embodiment of the first aspect, the method furtherincludes: measuring, by the user equipment, channel quality of at leastone of the plurality of beams in a plurality of consecutive preset timeperiods in response to the blocking of the serving beam; separatelycomparing, by the user equipment, a channel quality value in each timeperiod with a preset reliability threshold and a preset unreliabilitythreshold, where the preset reliability threshold is greater than thepreset unreliability threshold; and if channel quality measured in eachof the plurality of consecutive preset time periods is lower than thepreset unreliability threshold, starting, by the user equipment, apreset timer; or if channel quality measured in each of the plurality ofconsecutive preset time periods after the preset timer is started ishigher than the preset reliability threshold, terminating, by the userequipment, the preset timer; or if channel quality measured in none ofthe plurality of consecutive preset time periods after the preset timeris started is higher than the preset reliability threshold, and thepreset timer expires, triggering, by the user equipment, a cellreselection procedure.

According to a second aspect of embodiments of the present disclosure, acommunication method is provided, where user equipment can communicatewith a network device by using a plurality of beams, the plurality ofbeams include a first beam and at least one second beam, the first beamis a serving beam used by the user equipment to listen to controlinformation, the second beam is a beam other than the serving beam, andthe method includes: determining, by the network device, that theserving beam is blocked; and sending, by the network device, a firstmessage by using the first beam or the second beam.

With reference to the second aspect, in a first optional embodiment ofthe second aspect, the determining, by the network device, that theserving beam is blocked includes: if the network device does notreceive, within preset duration after the network device sends a secondmessage, a feedback message that is sent by the user equipment inresponse to the second message, determining, by the network device, thatthe serving beam is blocked; or

if the network device receives a blocking message that is sent by theuser equipment by using the first beam or the second beam, determining,by the network device, that the serving beam is blocked.

With reference to the second aspect, in a second optional embodiment ofthe second aspect, the method further includes: obtaining, by thenetwork device, a response message that is sent by the user equipment inresponse to the first message, where the response message is used toindicate a beam used by the user equipment to obtain the first message;and sending, by the network device, a beam switching message in responseto the response message, where the beam switching message is used toindicate that one of the plurality of beams is a next serving beam ofthe user equipment.

With reference to the second aspect, the first optional embodiment ofthe second aspect, or the second optional embodiment of the secondaspect, in a third optional embodiment of the second aspect, the secondbeam includes a plurality of beams.

With reference to the third optional embodiment of the second aspect, ina fourth optional embodiment of the second aspect, the sending, by thenetwork device, a first message by using the first beam or the secondbeam includes: sending, by the network device, the first message byusing the first beam and each second beam; or

sending, by the network device, the first message by using all beams ina preset beam combination, where the preset beam combination includesthe first beam, or the first beam and any quantity of second beams; or

selecting, by the network device, a corresponding single beam from thefirst beam and all second beams at different time points by using apreconfigured correspondence between a beam and a time point; andsending the first message by using the selected single beam; or

sending, by the network device, the first message by using all the beamsin the preset beam combination; if the response message that is sent bythe user equipment in response to the first message is received on noneof the beams in the preset beam combination, selecting a correspondingsingle beam from the plurality of beams or a beam outside the presetbeam combination at different time points by using a preconfiguredcorrespondence between a beam and a time point; and sending the firstmessage by using the selected single beam.

With reference to the first optional embodiment of the second aspect, ina fifth optional embodiment of the second aspect, the first messagecarries one piece or a combination of indication information and datainformation.

With reference to the fifth optional embodiment of the second aspect, ina sixth optional embodiment of the second aspect, the indicationinformation is a PDCCH order; and the obtaining, by the network device,a response message that is sent by the user equipment in response to thefirst message includes: receiving, by the network device, a preamblethat is sent by the user equipment by using one or more beams.

With reference to the sixth optional embodiment of the second aspect, ina seventh optional embodiment of the second aspect, the method furtherincludes: if the preamble is received by using one beam, determining, asa next serving beam by the network device, the beam used by thepreamble; or if the preamble is received by using at least two beams,determining, by the network device, a beam with a greatest communicationquality value in the at least two beams as a next serving beam; or ifthe preamble is received by using at least two beams, determining, as anext serving beam by the network device, a beam used by a last receivedpreamble; and the sending, by the network device, a beam switchingmessage in response to the response message includes: sending, by thenetwork device, identification information of the next serving beam inresponse to the response message.

With reference to the fifth optional embodiment of the second aspect, inan eighth optional embodiment of the second aspect, the indicationinformation is uplink scheduling indication information; and theobtaining, by the network device, a response message that is sent by theuser equipment in response to the first message includes: receiving, bythe network device, a measurement report that is of all of the pluralityof beams and that is sent by the user equipment by using one beam.

With reference to the eighth optional embodiment of the second aspect,in a ninth optional embodiment of the second aspect, the method furtherincludes: determining, as a next serving beam by the network device, abeam with a greatest signal power in all of the plurality of beams inresponse to the measurement report; and the sending, by the networkdevice, a beam switching message in response to the response messageincludes: sending, by the network device, identification information ofthe next serving beam.

According to a third aspect of embodiments of the present disclosure, acommunications apparatus is provided, applied to user equipment, wherethe user equipment can communicate with a network device by using aplurality of beams, the plurality of beams include a first beam and atleast one second beam, the first beam is a serving beam used by the userequipment to listen to control information, the second beam is a beamother than the serving beam, and the apparatus includes: a processingmodule, configured to determine that the serving beam is blocked; and areceiving module, configured to obtain a first message from the networkdevice by using the first beam or the second beam.

With reference to the third aspect, in a first optional embodiment ofthe third aspect, the apparatus further includes: a sending module,configured to send a response message in response to the first message,where the response message is used to indicate a beam used by thereceiving module to obtain the first message.

With reference to the first optional embodiment of the third aspect, ina second optional embodiment of the third aspect, the receiving moduleis further configured to obtain a beam switching message that is sent bythe network device in response to the response message, where the beamswitching message is used to indicate that one of the plurality of beamsis a next serving beam of the user equipment.

With reference to the third aspect, in a third optional embodiment ofthe third aspect, the sending module is further configured to send ablocking message by using a preset uplink resource, where the blockingmessage is used to instruct the network device to send the first messagein response to the blocking message.

With reference to the first, the second, or the third optionalembodiment of the third aspect, in a fourth optional embodiment of thethird aspect, the second beam includes a plurality of beams.

With reference to the fourth optional embodiment of the third aspect, ina fifth optional embodiment of the third aspect, that the receivingmodule is configured to obtain a first message from the network deviceby using the first beam or the second beam is specifically: thereceiving module is configured to receive, on the first beam and eachsecond beam, the first message sent by the network device; or

the receiving module is configured to: search for all beams in a presetbeam combination, where the preset beam combination includes the firstbeam, or the first beam and any quantity of second beams; and receivethe first message that is sent by the network device by using any one ormore beams in the preset beam combination; or

the receiving module is configured to: select, at different time pointsby using a preconfigured correspondence between a beam and a time point,a corresponding single beam from the first beam and all second beams forperforming a search; and receive the first message that is sent by thenetwork device by using the selected single beam; or

the receiving module is configured to: search for all the beams in thepreset beam combination; when the first message is received on none ofthe beams in the preset beam combination, select, at different timepoints by using a preconfigured correspondence between a beam and a timepoint, a corresponding single beam from a beam outside the preset beamcombination for performing a search; and receive the first message thatis sent by the network device by using the selected single beam.

With reference to the first optional embodiment of the third aspect, ina sixth optional embodiment of the third aspect, the first messagecarries one piece or a combination of indication information and datainformation.

With reference to the sixth optional embodiment of the third aspect, ina seventh optional embodiment of the third aspect, the indicationinformation is a PDCCH order; the processing module is furtherconfigured to generate a preamble in response to the PDCCH order; andthat the sending module is configured to send a response message inresponse to the first message is specifically: the sending module isconfigured to send the preamble on a preset random access resource in abeam used by the first message; or

the sending module is configured to send the preamble on a preset randomaccess resource in all beams used by the first message; or

the sending module is configured to: determine a beam with a greatestsignal power in all beams used by the first message, and send thepreamble on a preset random access resource in the beam with thegreatest power; or

the sending module is configured to: after sending the preamble on apreset random access resource in a beam on which the first message isreceived, receive the first message from another beam, and if a signalpower of the another beam is greater than a signal power of the previousbeam, send the preamble on a preset random access resource in theanother beam.

With reference to the sixth optional embodiment of the third aspect, inan eighth optional embodiment of the third aspect, the indicationinformation is uplink scheduling indication information; the processingmodule is further configured to determine a measurement report thatincludes communication quality of all beams; and that the sending moduleis configured to send a response message in response to the firstmessage is specifically: the sending module is configured to send themeasurement report by using a preset time-frequency resource in any beamused by the first message.

With reference to the second optional embodiment of the third aspect, ina ninth optional embodiment of the third aspect, the processing moduleis further configured to: measure channel quality of at least one of theplurality of beams in a plurality of consecutive preset time periods inresponse to the blocking of the serving beam; separately compare achannel quality value in each time period with a preset reliabilitythreshold and a preset unreliability threshold, where the presetreliability threshold is greater than the preset unreliabilitythreshold; and if channel quality measured in each of the plurality ofconsecutive preset time periods is lower than the preset unreliabilitythreshold, start a preset timer; or if channel quality measured in eachof the plurality of consecutive preset time periods after the presettimer is started is higher than the preset reliability threshold,terminate the preset timer; or if channel quality measured in none ofthe plurality of consecutive preset time periods after the preset timeris started is higher than the preset reliability threshold, trigger acell reselection procedure.

According to a fourth aspect of embodiments of the present disclosure, acommunications apparatus is provided, applied to a network device, whereuser equipment can communicate with the network device by using aplurality of beams, the plurality of beams include a first beam and atleast one second beam, the first beam is a serving beam used by the userequipment to listen to control information, the second beam is a beamother than the serving beam, and the apparatus includes: the processingmodule, configured to determine that the serving beam is blocked; andthe sending module, configured to send a first message by using thefirst beam or the second beam.

With reference to the fourth aspect, in a first optional embodiment ofthe fourth aspect, the apparatus further includes a receiving module;and that the processing module is configured to determine that theserving beam is blocked is specifically: if the receiving module doesnot receive, within preset duration after the network device sends asecond message, a feedback message that is sent by the user equipment inresponse to the second message, the processing module is configured todetermine that the serving beam is blocked; or

if the receiving module receives a blocking message that is sent by theuser equipment by using the first beam or the second beam, theprocessing module is configured to determine that the serving beam isblocked.

With reference to the fourth aspect, in a second optional embodiment ofthe fourth aspect, the receiving module is further configured to obtaina response message that is sent by the user equipment in response to thefirst message, where the response message is used to indicate a beamused by the user equipment to obtain the first message; and the sendingmodule is further configured to send, by the network device, a beamswitching message in response to the response message, where the beamswitching message is used to indicate that one of the plurality of beamsis a next serving beam of the user equipment.

With reference to the fourth aspect, the first optional embodiment ofthe fourth aspect, or the second optional embodiment of the fourthaspect, in a third optional embodiment of the fourth aspect, the secondbeam includes a plurality of beams.

With reference to the third optional embodiment of the fourth aspect, ina fourth optional embodiment of the fourth aspect, that the sendingmodule is configured to send a first message by using the first beam orthe second beam is specifically: the sending module is configured tosend the first message by using the first beam and each second beam; or

the sending module is configured to send the first message by using allbeams in a preset beam combination, where the preset beam combinationincludes the first beam, or the first beam and any quantity of secondbeams; or

the sending module is configured to: select a corresponding single beamfrom the first beam and all second beams at different time points byusing a preconfigured correspondence between a beam and a time point;and send the first message by using the selected single beam; or

the sending module is configured to: send the first message by using allthe beams in the preset beam combination; if the response message thatis sent by the user equipment in response to the first message isreceived on none of the beams in the preset beam combination, select acorresponding single beam from the plurality of beams or a beam outsidethe preset beam combination at different time points by using apreconfigured correspondence between a beam and a time point; and sendthe first message by using the selected single beam.

With reference to the first optional embodiment of the fourth aspect, ina fifth optional embodiment of the fourth aspect, the first messagecarries one piece or a combination of indication information and datainformation.

With reference to the fifth optional embodiment of the fourth aspect, ina sixth optional embodiment of the fourth aspect, the indicationinformation is a PDCCH order; and that the receiving module isconfigured to obtain a response message that is sent by the userequipment in response to the first message is specifically: thereceiving module is configured to receive a preamble that is sent by theuser equipment by using one or more beams.

With reference to the sixth optional embodiment of the fourth aspect, ina seventh optional embodiment of the fourth aspect, the processingmodule is further configured to: if the preamble is received by usingone beam, determine, as a next serving beam, the beam used by thepreamble; or if the preamble is received by using at least two beams,determine a beam with a greatest signal power in the at least two beamsas a next serving beam; or if the preamble is received by using at leasttwo beams, determine, as a next serving beam, a beam used by a lastreceived preamble; and that the sending module is configured to send abeam switching message in response to the response message isspecifically: the sending module is configured to send identificationinformation of the next serving beam in response to the responsemessage.

With reference to the fifth optional embodiment of the fourth aspect, inan eighth optional embodiment of the fourth aspect, the indicationinformation is uplink scheduling indication information; and that thereceiving module is configured to obtain a response message that is sentby the user equipment in response to the first message is specifically:the receiving module is configured to receive a measurement report thatis of all of the plurality of beams and that is sent by using one beam.

With reference to the eighth optional embodiment of the fourth aspect,in a ninth optional embodiment of the fourth aspect, the processingmodule is further configured to determine, as a next serving beam, abeam with a greatest signal power in all of the plurality of beams inresponse to the measurement report; and that the sending module isconfigured to send a beam switching message in response to the responsemessage is specifically: the sending module is configured to sendidentification information of the next serving beam in response to theresponse message.

According to a fifth aspect of embodiments of the present disclosure, acommunications system is provided, including user equipment and anetwork device, where the user equipment may include the communicationsapparatus according to any optional embodiment of the third aspect, andthe network device may include the communications apparatus according toany optional embodiment of the fourth aspect.

According to the method provided in the embodiments of the presentdisclosure, the UE may determine that the serving beam is blocked, andfurther obtain the first message sent by the network device, therebyeliminating an adverse effect caused by the blocking of the servingbeam. Correspondingly, the network device may also determine that theserving beam is blocked, and further send the first message, therebyeliminating an adverse effect caused by the blocking of the servingbeam.

Further, the next serving beam may be determined through informationexchange, so that the UE is handed over from a previous serving beam tothe next serving beam, and recovers communication with the networkdevice.

It should be understood that the foregoing general description and thefollowing detailed description are merely examples and explanations, andcannot limit the present disclosure.

In other embodiments, there is provided a communications system,including user equipment and a network device, wherein the userequipment is as described according to any embodiment, aspect oroptional implementation set forth above, and the network device is asdescribed according to any embodiment, aspect or optional implementationset for the above.

In other embodiments, there is provided a computer-readable storagemedium or computer program product, including instructions which, whenexecuted by a device, cause the device to perform any of the methods asdescribed according to any embodiment, aspect or optional implementationset forth above.

In other embodiments, there is provided an apparatus including a memory,a processor, and a computer program stored in the memory which, whenexecuted by the processor, causes the apparatus to implement any of themethods as described according to any embodiment, aspect or optionalimplementation set forth above.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure or in the prior art more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments or the prior art. Apparently, a person of ordinary skill inthe art may derive other drawings from these accompanying drawingswithout creative efforts. In addition, the description does notconstitute a limitation on the embodiments, elements that have a samereference sign number in the accompanying drawings indicate similarelements, and unless otherwise stated, a figure in the accompanyingdrawings does not constitute a proportional limitation.

FIG. 1 is a schematic diagram of base station coverage according to anembodiment of the present disclosure;

FIG. 2 is a schematic diagram of a TRP layout according to an embodimentof the present disclosure;

FIG. 3 is a schematic diagram of signaling of a communication methodaccording to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of signaling of a communication methodaccording to another embodiment of the present disclosure;

FIG. 5 is a schematic diagram of SR resource allocation according to anembodiment of the present disclosure;

FIG. 6 is a schematic diagram of SR resource allocation according toanother embodiment of the present disclosure;

FIG. 7 is a schematic flowchart of a communication method according toan embodiment of the present disclosure;

FIG. 8 is a schematic diagram of cell triggering according to anembodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of a communications apparatusaccording to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of user equipment according toan embodiment of the present disclosure;

FIG. 11 is a schematic structural diagram of another communicationsapparatus according to an embodiment of the present disclosure; and

FIG. 12 is a schematic structural diagram of a network device accordingto an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Example embodiments are described in detail herein, and examples of theexample embodiments are presented in the accompanying drawings. When thefollowing description relates to the accompanying drawings, unlessspecified otherwise, same numbers in different accompanying drawingsrepresent a same or similar element. Implementations described in thefollowing example embodiments do not represent all implementationsconsistent with the present disclosure. On the contrary, they are onlyexamples of apparatuses and methods that are described in the appendedclaims in detail and that are consistent with some aspects of thepresent disclosure.

For example, embodiments of the present disclosure may be used for acellular communications system, for example, may be used for a Long TermEvolution (LTE) cellular communications system, or may be used for a 5Gor new radio (NR) communications system.

For the LTE communications system, there are a plurality of cells ofeach evolved NodeB (eNodeB, eNB). An eNB in each cell may use aplurality of beams to complete cell coverage. For example, as shown inFIG. 1, an eNB in FIG. 1 is a base station in the LTE system. A coveragearea is expanded by forming a narrow beam (which may be simply referredto as a beam below) in a downlink direction, and receiving may also beperformed in beam domain in an uplink direction.

For the 5G or NR system, there may be one or more transmission receptionpoints (TRP) of a new radio NodeB (NR-NB). A TRP is a wireless signaltransceiver unit in the 5G or NR system. A coverage area is expanded byforming a narrow beam in a downlink direction, and receiving may also beperformed in beam domain in an uplink direction. For example, as shownin FIG. 2, each TRP can form a plurality of beams to communicate withUE.

The UE determines an available beam by searching for a pilot signal sentby the eNB or the TRP, and feeds back a selection result to the eNB orthe TRP. In addition, if a plurality of antennas are deployed on a UEside, a beamforming transceiving technology may also be used on the UEside.

FIG. 3 is a schematic diagram of signaling of a communication methodaccording to an example embodiment of the present disclosure. Thecommunication method is applied to a communications system that includesuser equipment UE and a network device, and the user equipment cancommunicate with the network device by using a plurality of beams. Inthis embodiment, the UE does not have an uplink resource used forfeeding back, to the network device (for example, a base station), acase in which a serving beam is blocked.

S301. The UE determines that a serving beam is blocked.

In this embodiment, that the serving beam is blocked means that signalquality of the serving beam of the UE is lower than a first threshold.For example, in a particular scenario, a case in which signal quality ofa beam received on a UE side suddenly falls below the first thresholdmay occur, in other words, a beam blocking phenomenon occurs. In thiscase, normal communication between the UE and the network device isblocked. For the network device, the UE in this case is in an offlinestate to some extent.

When the serving beam is blocked, usually, the UE may first find thecase by measuring beam quality in real time. For example, when the UEfinds that a reference signal received power (RSRP) of the serving beamis less than the first threshold, it may be considered that the servingbeam is blocked. For example, the first threshold may be notified to theUE by using a radio resource control (RRC) message or specified in acommunications protocol, and the first threshold may usually correspondto a minimum RSRP that can be used to accurately detect a physicaldownlink control channel (PDCCH).

S302. The UE enables a beam search function.

For the UE, if no uplink resource is preset for the UE to feed back abeam measurement result, the case in which the serving beam is blocked,or the like to the network device, to recover communication, the UE candetermine, only by searching for information delivered by the networkdevice, whether a beam that can be used to establish communication withthe network device exists.

In this embodiment of the present disclosure, after the serving beam isblocked, the UE starts a blind search (in other words, an attempt), tobe specific, the UE searches for the first message from the networkdevice on one or more of the plurality of beams, so as to re-establishcommunication with the network device by using these beams on which thefirst message is found.

A specific search range may be configured by the network device orspecified in a protocol. For example, the UE may search for control orscheduling information on a plurality of downlink beams, for example,the UE searches for a PDCCH indication by using a cell radio networktemporary identifier (C-RNTI). If the UE can search for the plurality ofbeams at the same time, the UE may search for the plurality of beams atthe same time. However, if the UE has a limited capability and canperform detection only on a single beam at any time point, the networkdevice may preconfigure a correspondence between a beam and a time pointand notify the UE, and further, the UE may search for different beams atdifferent time points based on the correspondence. In addition, in thisembodiment of the present disclosure, to improve search efficiency ofthe UE, the network device may further preconfigure a manner in whichthe UE searches for a beam. For example, the UE searches for a presetbeam combination at the same time. When the first message is not found,in consideration of a power or another factor, the UE searches for asingle beam in remaining beams based on the correspondence between abeam and a time point. For example, the preset beam combination includesat least the serving beam, and may further include a candidate beam or abeam with better communication quality selected based on a current beammeasurement result, and the candidate beam is a beam that is mostrecently reported by the UE to the network device other than the servingbeam.

In this embodiment of the present disclosure, the first message is notlimited in this embodiment. For example, the first message may be uplinkscheduling information, downlink scheduling information that carriesdownlink data, downlink scheduling information that does not carrydownlink data, configuration information, downlink data, or the like.Usually, only if the first message is information sent by the networkdevice, it may indicate that a current beam may be used by the UE.

S303. A network device determines that the serving beam of the UE isblocked.

For example, when the network device finds, after sending data to the UEby using the serving beam of the UE, that the UE does not performcorresponding feedback, it may be considered that the serving beam ofthe UE is abnormal, in other words, blocking occurs.

For example, if the network device does not receive, within presetduration after sending the downlink data to the UE, acknowledgement(ACK) or negative acknowledgement (NACK) information fed back by the UE,or if the network device does not receive, within preset duration aftersending the uplink scheduling to the UE, data sent by the UE to thenetwork device, the network device may consider that the serving beam ofthe UE is abnormal.

S304. The network device sends a first message by using the first beamor a second beam.

In this embodiment, the UE does not have the uplink resource used forfeeding back, to the network device, the case in which the serving beamis blocked, to be specific, the network device cannot learn of a statusof the UE. Therefore, the network device may send the first message tothe UE, so as to determine an available beam between the network deviceand the UE by using feedback information of the UE in response to thefirst message.

When sending the first message, the network device may use a randomsending policy, to be specific, the network device randomly selects anyone or more beams to send the first message. Because the network deviceuses the random sending policy, the UE does not know the sending policyof the network device, and further, the UE may find, through blindsearch, the first message sent by the network device.

In addition, the network device may further send the first messageaccording to a preset sending policy. For example, according to thepreset sending policy, on the one or more of the plurality of beams, thenetwork device periodically sends the first message or sends the firstmessage based on the preconfigured correspondence between a beam and atime point. When the network device sends the first message according tothe preset sending policy, although the UE may still receive the firstmessage in a blind search manner, to save energy consumption of the UEduring the blind search, the network device may further notify the UE ofthe preset sending policy in advance. Further, when searching, the UEmay pertinently search according to the preset sending policy, therebyimproving accuracy of the search, and reducing energy consumption whensearching for an unavailable beam.

In this embodiment of the present disclosure, although the serving beamof the UE is blocked, the network device still considers sending thefirst message on the serving beam. This considers that, because theserving beam may be affected by an obstacle or another external factor,signal quality suddenly greatly falls, but the signal quality of theserving beam may be recovered in a short time as the UE moves or theexternal factor is removed. Therefore, when sending the first message,the network device may still send the first message on the serving beam.

S305. The UE receives the first message by using the first beam or thesecond beam.

In this embodiment of the present disclosure, by performing step S302and step S305, the UE may obtain the first message from the networkdevice by using the first beam or the second beam.

At this point, the UE may determine that the serving beam is blocked,and further obtain the first message sent by the network device, therebyeliminating an adverse effect caused by the blocking of the servingbeam. Correspondingly, the network device may also determine that theserving beam is blocked, and further send the first message, therebyeliminating an adverse effect caused by the blocking of the servingbeam.

Further, in the communication method provided in this embodiment of thepresent disclosure, one or a combination of the following steps mayfurther be used based on the foregoing steps.

S306. The UE sends a response message in response to the first message.

The response message is used to indicate a beam used by the UE to obtainthe first message. In this embodiment of the present disclosure, theresponse message may also change accordingly based on different types offirst messages. For example, if finding the downlink data, the UE feedsback an ACK or a NACK based on a cyclic redundancy check (CRC) checkresult; and if finding the uplink scheduling, the UE sends data on acorresponding resource, and the like.

After finding the first message from the network device on any of theplurality of beams, the UE may perform corresponding feedback to thenetwork device. In this embodiment of the present disclosure, if the UEreceives the first message only by using one beam, when the UE feedsback the response message, the UE still sends the response message tothe network device by using the beam on which the first message isreceived. However, if the UE receives the first message by using two ormore beams, when the UE feeds back the response message, the UE may sendthe response message to the network device by using each beam on whichthe first message is received, or may select a beam from beams on whichthe first message is received, and then send the response message to thenetwork device by using the selected beam. When the beam is selected, abeam with highest signal quality may be used as a beam for sending theresponse message.

S307. The network device obtains the response message.

The response message is used to indicate the beam used by the UE toobtain the first message.

For details of a description of the response message and a manner ofsending the response message, refer to the description in step S306.Details are not described herein again.

S308. The network device sends a beam switching message in response tothe response message.

The beam switching message is used to indicate that one of the pluralityof beams is a next serving beam of the UE. In this embodiment of thepresent disclosure, the beam switching message may be a message usedwhen the UE is normally handed over from a beam in the art.

After receiving the response message sent by the UE, the network devicemay determine that a beam better than the current serving beam that isblocked may be used between the network device and the UE. Further, thenetwork device may redetermine one beam as the next serving beam of theUE, and claim the beam switching message, so that after receiving thebeam switching message, the UE may be handed over to the next servingbeam.

When receiving the response message of the UE only by using one beam,the network device directly determines, as the next serving beam, thebeam on which the response message is received. When receiving theresponse message of the UE by using two or more beams, the networkdevice may select, as the next serving beam, one beam from beams onwhich the response message is received. When the beam is selected, abeam with highest signal quality may be used as the next serving beam.

In this embodiment of the present disclosure, the beam switching messagemay carry identification information of the next serving beam. Inaddition, when the beam switching message is sent, the beam switchingmessage may be sent on the next serving beam, or may be sent on anyother beams on which the response message is received.

S309. The UE obtains the beam switching message that is sent by thenetwork device in response to the response message.

The beam switching message is used to indicate that the beam of theplurality of beams is the next serving beam of the UE.

After the UE receives the beam switching message, the UE may be handedover from the current serving beam to the next serving beam based on thebeam switching message. In this way, normal communication between the UEand the network device is recovered.

In the method provided in this embodiment of the present disclosure, thenext serving beam may be determined through information exchange, sothat the UE is handed over from a previous serving beam to the nextserving beam, and recovers communication with the network device.

In a scenario, that the network device sends the first message by usingone or a combination of the first beam and the second beam may includethe following manners:

Manner 1: The network device sends the first message by using the firstbeam and each second beam.

Manner 2: The network device sends the first message by using all beamsin the preset beam combination, and the preset beam combination includesthe first beam, or the first beam and any quantity of second beams.

For example, the preset beam combination includes at least the servingbeam, and may further include a candidate beam or a beam with bettercommunication quality selected based on a current beam measurementresult, and the candidate beam is a beam that is most recently reportedby the UE to the network device other than the serving beam.

To distinguish from Manner 1, in this embodiment of the presentdisclosure, a quantity of beams in the preset beam combination is lessthan a sum of a quantity of first beams and a quantity of second beams.For sending the first message on each beam in the preset beamcombination, refer to a manner of sending the first message in Manner 1.Details are not described herein again.

Manner 3:

The network device selects a corresponding single beam from the firstbeam and all second beams at different time points by using thepreconfigured correspondence between a beam and a time point, and sendsthe first message by using the selected single beam.

Manner 4:

The network device sends the first message by using all the beams in thepreset beam combination; if the response message that is sent by the UEin response to the first message is received on none of the beams in thepreset beam combination, selects a corresponding single beam from theplurality of beams or a beam outside the preset beam combination atdifferent time points by using the preconfigured correspondence betweena beam and a time point; and sends the first message by using theselected single beam.

For example, this may be divided into two phases. In a first phase, thefirst message is sent to the UE by using all the beams in the presetbeam combination. When the first message is sent on each beam in thefirst phase, different beams may be used at different time points (at asubframe level or a symbol level).

If a feedback of the UE is still not obtained through the sending of thefirst phase, sending may be performed in a second phase, to be specific,the first message is sent to the UE on all the beams or on all beamsexcept a beam in the first phase. In addition, in the second phase, toreduce system resource consumption, the first message may be sent onlyat a preset time point on each beam, to be specific, the first messagemay be sent to the UE only at a corresponding time point on each of allthe beams or all the beams except the beam in the first phase based onthe configured correspondence between a beam and a time point, and thecorrespondence between a beam and a time point may be notified by thenetwork device to the UE or specified in a protocol. In addition, toreduce resource consumption, in the second phase, the network device mayalternatively send a PDCCH but does not carry the downlink data.

The foregoing enumerated four manners are example descriptions used forease of understanding this embodiment of the present disclosure, aperson skilled in the art easily figures out other similar manners basedon the foregoing four manners, and these similar manners also fallwithin the protection scope of the present disclosure.

In Manner 1 and Manner 2 in the foregoing scenario, the network devicemay send the first message to the UE by using the plurality of beams atthe same time. However, in another scenario, if the network devicecannot send data to the UE by using the plurality of beams at the sametime, the network device may send the data to the UE in a time divisionmanner only by using a limited quantity of beams at any time, andtraverse all the beams over a period of time, such as Manner 3 andManner 4 in the foregoing scenario.

For example, the network device may select two modes on a plurality ofdifferent beams for sending the data (retransmission). Mode 1: Thenetwork device performs retransmission M times on the single beam (M isspecified in a protocol or is implemented depending on the networkdevice), and sequentially traverses all the beams, where a sequence oftraversal may start from an optimal beam and end with a worst beam basedon a previous measurement result; or transmits data on the plurality ofbeams at the same time. Mode 2: The network device performsretransmission only once on the single beam, sequentially traverses allthe beams to complete one round of retransmission, and may complete Nrounds of transmission in total (N is specified in the protocol ordepends on the base station for implementation). The data retransmittedeach time may be an uplink grant (UL Grant) or an uplink schedulingindication, downlink assignment (DL Assignment) or a downlink schedulingindication and downlink data, another PDCCH indication, or the like.

In a scenario, that the UE searches for the first message from thenetwork device on one or a combination of the first beam and the secondbeam may include the following manners:

Manner 1: The UE receives, on the first beam and each second beam, thefirst message sent by the network device.

Manner 2:

The UE searches for all the beams in the preset beam combination, wherethe preset beam combination includes the first beam, or the first beamand any quantity of second beams; and receives the first message that issent by the network device by using any one or more beams in the presetbeam combination.

Manner 3:

The UE selects, at different time points by using the preconfiguredcorrespondence between a beam and a time point, a corresponding singlebeam from the first beam and all second beams for performing a search,and receives the first message that is sent by the network device byusing the selected single beam.

Manner 4:

The UE searches for all the beams in the preset beam combination; whenthe first message is received on none of the beams in the preset beamcombination, selects, at different time points by using thepreconfigured correspondence between a beam and a time point, acorresponding single beam from a beam outside the preset beamcombination for performing a search; and receives the first message thatis sent by the network device by using the selected single beam.

The network device may preconfigure the correspondence between a beamand a time point, and the network device notifies the UE of thepreconfigured correspondence between a beam and a time point in advance.

The foregoing enumerated four manners are example descriptions used forease of understanding this embodiment of the present disclosure, aperson skilled in the art easily figures out other similar manners basedon the foregoing four manners, and these similar manners also fallwithin the protection scope of the present disclosure.

In a scenario, the first message may be a physical downlink controlchannel PDCCH order that triggers random access.

In response to the PDCCH order, the UE may generate a preamble as theresponse message. In addition, that the UE sends a response message inresponse to the first message may include the following manners:

Manner 1: The UE sends the preamble on a preset random access resourcein a beam used by the first message.

When the UE receives the PDCCH order by using a beam, the UE selects,based on the beam used when the PDCCH order is received and a configuredcorrespondence between a beam and a random access resource, acorresponding access resource on the beam used when the PDCCH order isreceived, for sending the preamble, so that the network device learns ofthe beam used when the UE receives the PDCCH order.

Manner 2: The UE sends the preamble on a preset random access resourcein all beams used by the first message.

When the UE receives the PDCCH order by using a plurality of beams, theUE may further separately select, based on a correspondence between eachbeam and a random access resource, a corresponding access resource oneach beam, for sending the preamble, so that the network device learnsof a beam used when the UE receives the PDCCH order.

Manner 3:

The UE determines a beam with a greatest communication quality value inall beams used by the first message, and sends the preamble on a presetrandom access resource in the determined beam.

When the UE receives the PDCCH order by using a plurality of beams, theUE may further select a beam from the plurality of beams, determine thebeam with the greatest communication quality value as a sending beam ofthe first message, and send the first message on the beam. In thisembodiment of the present disclosure, a communication quality value is avalue that may be commonly used to reflect beam quality in the art, forexample, a reference signal received power (RSRP), and reference signalreceived quality (RSRQ).

In this manner, when receiving the PDCCH order by using the plurality ofbeams, the UE selects a beam with optimal communication quality whensending the first message, so that the network device may subsequentlydetermine the beam with optimal communication quality as the nextserving beam, thereby improving communication quality when the UE usesthe next serving beam.

Manner 4:

After sending the preamble on a preset random access resource in a beamon which the first message is received, the UE receives the firstmessage from another beam, and if a communication quality value of theanother beam is greater than a communication quality value of theprevious beam, sends the preamble on a preset random access resource inthe another beam.

When the UE receives the PDCCH order by using the plurality of beams,the UE may further compare signal quality of each beam on which thePDCCH order is received, and first send the preamble according to afirst received PDCCH order. Then, if signal quality of a subsequent beamis higher than that of a first beam, the UE sends the preamble accordingto a PDCCH order of the beam. Next, if signal quality of a subsequentbeam is higher than signal quality of a current optimal beam, the UEsends the preamble according to a PDCCH order of the beam. In thismanner, a last preamble sent by the UE corresponds to the currentoptimal beam. Based on a sequence in which the network device receivesthe preamble by using a beam, the network device can conveniently learnof communication quality of the beam and master an optimal beam.

The foregoing enumerated four manners are example descriptions used forease of understanding this embodiment of the present disclosure, aperson skilled in the art easily figures out other similar manners basedon the foregoing four manners, and these similar manners also fallwithin the protection scope of the present disclosure.

Corresponding to the foregoing plurality of manners of sending theresponse message by the UE, before sending the beam switching message,the network device may determine the next serving beam in a plurality ofmanners.

Manner 1: If the preamble is received by using one beam, the networkdevice determines, as the next serving beam, the beam used by thepreamble.

Referring to Manner 1 and Manner 3 of sending the response message bythe UE, the preamble received by the network device has only one beam.Therefore, the network device may determine, as the next serving beam,the beam used by the preamble.

Manner 2: If the preamble is received by using at least two beams, thenetwork device determines a beam with a greatest signal power in the atleast two beams as the next serving beam.

Referring to Manner 2 of sending the response message by the UE, becausethe UE sends the response message by using the plurality of beams, thenetwork device receives the preamble by using the at least two beams. Inthis case, the network device measures communication quality of eachbeam, and then determines a beam with a greatest communication qualityvalue as the next serving beam.

Manner 3: If the preamble is received by using at least two beams, thenetwork device determines, as the next serving beam, a beam used by alast received preamble.

Referring to Manner 4 of sending the response message by the UE, the UEsends the response message on the plurality of beams once, and beamcommunication quality of the subsequent beam used to send the preambleis better than that of the previous beam used to send the preamble.Therefore, the network device may learn that communication quality ofthe beam used by the last received preamble is optimal, and may furtherdetermine, as the next serving beam, the beam used by the last receivedpreamble.

Regardless of a manner of determining the next serving beam, whendelivering the beam switching message, the network device may directlysend the identification information of the next serving beam to the UE,so that the UE may be handed over the next serving beam.

In another scenario, the first message may be an uplink scheduling grantUL Grant sent by using a PDCCH.

In response to the UL Grant, the UE measures communication quality ofall beams, and obtains a measurement report of all the beams as theresponse message.

Correspondingly, when sending the response message to the networkdevice, the UE may send the measurement report to the network device byusing a preset time-frequency resource in any beam used by the firstmessage.

That the network device determines the next serving beam based on theresponse message may include:

determining, as the next serving beam, a beam with a greatest signalpower in all of the plurality of beams in response to the measurementreport; and

using, by the network device, the identification information of the nextserving beam as the beam switching message, and sending the beamswitching message to the UE.

In a manner of sending the UL Grant, the UE only needs to report beaminformation on a resource indicated by the first UL Grant, for example,a measurement result of the plurality of beams. Then, the network devicemay select an optimal beam to send downlink data, and the UE also onlyneeds to listen to data on the optimal beam.

FIG. 4 is a schematic diagram of signaling of a communication methodaccording to an example embodiment of the present disclosure. In thisembodiment, UE can feed back, to a base station by using an uplinkresource, a case in which a serving beam is blocked.

S401. The UE determines that a serving beam is blocked.

S402. The UE sends a blocking message by using a preset uplink resource.

The blocking message is used to instruct the network device to send thefirst message in response to the blocking message.

S403. A network device sends a first message by using the first beam ora second beam.

After receiving the blocking message that is sent by the UE by using thepreset uplink resource, the network device may determine that theserving beam of the UE is blocked. In this case, the network device doesnot know whether there is still an available beam between the networkdevice and the UE. Therefore, the network device sends the first messageby using the first beam or the second beam, to attempt to communicatewith the UE, thereby finding the available beam.

S404. The UE receives the first message by using the first beam or thesecond beam.

In this embodiment of the present disclosure, the UE may enable a beamsearch function after detecting that the serving beam is blocked, or mayenable a beam search function after sending the blocking message on thepreset uploading resource.

At this point, the UE may determine that the serving beam is blocked,notify the network device of the case in which the serving beam isblocked, and further obtain the first message sent by the networkdevice, thereby eliminating an adverse effect caused by the blocking ofthe serving beam. Correspondingly, after receiving the blocking messagesent by the UE, the network device may send the first message to the UE,thereby eliminating an adverse effect caused by the blocking of theserving beam.

Further, in the communication method provided in this embodiment of thepresent disclosure, one or a combination of the following steps mayfurther be used based on the foregoing steps.

S405. The UE sends a response message in response to the first message.

S406. The network device obtains the response message.

S407. The network device sends a beam switching message in response tothe response message.

In the method provided in this embodiment of the present disclosure, anext serving beam may be determined through information exchange, sothat the UE is handed over from a previous serving beam to the nextserving beam, and recovers communication with the network device.

A difference between this embodiment of the present disclosure and theembodiment shown in FIG. 3 is that, in this embodiment, a manner inwhich the network device learns that the serving beam of the UE isblocked is not that the network device detects whether feedbackinformation of the UE is received after sending information to the UEbut that the network device directly receives the blocking message sentby using the preset uplink resource. Therefore, in this embodiment ofthe present disclosure, for a same step, refer to a correspondingdescription in the embodiment shown in FIG. 3. Details are not describedherein again.

In a scenario, the preset uplink resource may be a dedicated uplinkscheduling request (SR) resource. The SR resource is a periodicallyconfigured resource indicated by two parameters, where sr-ConfigIndexspecifies a period of the SR and a subframe offset of the SR in theperiod, to be specific, determines a time location of the SR resource;and sr-PUCCH-ResourceIndex specifies an SR resource index number at asingle moment, and the SR resource index number is used to correspond toa specific SR resource frequency domain location and a code resource.Optionally, a plurality of SR resources are allocated to single UE inone period of the SR, to be specific, one sr-ConfigIndex matches aplurality of sr-PUCCH-ResourceIndex. A mapping mode is shown in FIG. 5,and an example of the plurality of SR resources in a same SR period ofand with a same offset is shown in the figure.

In another scenario, alternatively, a plurality of sr-ConfigIndex may beallocated to single UE, and match one or more sr-PUCCH-ResourceIndex,and a plurality of SR resources are separated on differenttime-frequency resources. A mapping mode is shown in FIG. 6, and anexample of the plurality of SR resources in different SR periods andwith different offsets is shown in the figure.

An example is used for description in the following.

If two SR resources are allocated to the UE, one is an uplink resourceused for normal application, after receiving data sent on the SR, thebase station delivers uplink scheduling to the UE by using a currentserving beam; and the other is used to indicate that the current servingbeam of the UE is blocked. After receiving data sent on the other SR,the base station delivers uplink scheduling to the UE by using step S404in the embodiment shown in FIG. 4.

In addition, more than two SR resources may be further allocated to theUE, one is an uplink resource used for normal application, other SRs areused to indicate that the current serving beam of the UE is blocked, andeach SR corresponds to different beams or beam combinations. Afterreceiving data sent on the other SRs, the base station learns that thecurrent serving beam is blocked, and also learns that a current optimalbeam is which beam or in which beam combination (a classification ruleof the beam combination is notified by the base station to the UE inadvance or specified in a protocol).

In another scenario, the preset uplink resource may be an uplinkreference signal resource. The network device allocates a dedicateduplink reference signal resource to the UE, including but not limited toa demodulation reference signal (DMRS) or a sounding reference signal(SRS). When the UE sends a corresponding reference signal, the basestation may know that the current serving beam is blocked, and deliverindication information to the UE by using step S404 in the embodimentshown in FIG. 4, and the indication information may be an uplinkscheduling indication or a PDCCH order that triggers random access.

In the foregoing embodiment, after the serving beam of the UE isblocked, communication between the UE and the network device arerecovered as soon as possible by searching for and switching to a nextserving beam. However, when the serving beam is blocked, the UE startssearching for another beam to detect information that may be sent by thebase station, or sends the blocking message to the base station on anavailable uplink resource at the same time, but finally needs to receivethe serving beam switching message of the base station, and needs to behanded over from the serving beam to another available beam, to recoverfrom beam blocking. If the serving beam switching instruction sent bythe base station is never obtained, and signal quality of the currentserving beam is always lower than a particular threshold, communicationof the UE is severely affected, greatly reducing communication qualityof the UE.

Optionally, after the serving beam of the UE is blocked, in anembodiment of the present disclosure, in the communication method, oneor a combination of the following steps may further be used based on theembodiments shown in FIG. 3 and FIG. 4, as shown in FIG. 7.

S501. The UE measures channel quality of the serving beam in a pluralityof consecutive preset time periods in response to the blocking of theserving beam.

In this embodiment of the present disclosure, only the channel qualityof the serving beam of the UE may be measured. In another embodiment,channel quality of two or more beams may be further measured. Fordetails, refer to a description in the other embodiment.

S502. The UE separately compares a channel quality value in each timeperiod with Qout, and determines whether the channel quality measured ineach of the plurality of consecutive preset time periods is lower thanQout.

If the channel quality measured in each of the plurality of consecutivepreset time periods is lower than Qout, step S503 is performed. If thechannel quality measured in each of the plurality of consecutive presettime periods is not lower than Qout, go back to step S502 for continuingto make a comparison.

In this embodiment of the present disclosure, a preset reliabilitythreshold is represented by Qin, a preset unreliability threshold isrepresented by Qout, and Qout is not a determining criterion used whenthe serving beam is blocked. In addition, the preset reliabilitythreshold is greater than the preset unreliability threshold.

For measuring only the channel quality of the serving beam, during thecomparison in step S502, the channel instruction of the serving beam maybe directly compared with Qin and Qout.

S503. The UE starts a preset timer.

S504. The UE separately compares the channel quality value in each timeperiod with Qin, and determines whether the channel quality measured ineach of the plurality of consecutive preset time periods after thepreset timer is started is higher than Qin.

After the preset timer is started, if the channel quality measured ineach of the plurality of consecutive preset time periods after thepreset timer is started is higher than Qin, step S505 is performed.

5505. The UE terminates the preset timer.

5506. If the channel quality measured in all of the plurality ofconsecutive preset time periods after the preset timer is started is nothigher than Qin, and the preset timer expires, the UE triggers a cellreselection procedure.

In this embodiment of the present disclosure, if the preset timerexpires, it indicates that an RLF occurs, to be specific, no availablebeam exists in a current cell. Therefore, cell reselection needs to beperformed, so that the UE may communicate by using a beam in anothercell.

In the method provided in this embodiment of the present disclosure,after the serving beam of the UE is blocked, if the UE does not receivethe serving beam switching instruction for a long time, and the qualityof the serving beam is always lower than a preset threshold, the UEperforms a radio link failure (RLF) determining procedure. If thequality of the serving beam becomes better or the serving beam switchinginstruction of the base station is received in this process, the UEexits from the RLF determining procedure. If the quality of the servingbeam does not become better or the serving beam switching instruction ofthe base station is not received in this process, once it is determinedthat the RLF occurs, finally, the cell reselection is restarted and arandom access procedure is performed.

When measuring the channel quality of the two or more beams, the UEfirst obtains beam scanning time information, to be specific, timeinformation of occurrence of each related beam. The information mayindicate a period in which a beam or a subarray occurs and a time pointin a period.

After receiving the time information, for radio link monitoring(RLM)/radio resource management (RRM) measurement of the UE, the UEmeasures quality of each beam based on a beam occurrence momentspecified by the time information. For RRM measurement (RSRP/RSRQ), theUE performs sampling and measurement on each beam only based on the beamoccurrence moment specified by the time information, to obtain anRSRP/RSRQ value of each beam. For RLM measurement (RSRP/RSRQ), the UEperforms sampling and measurement on each beam only based on the beamoccurrence moment specified by the time information, to obtain anRSRP/RSRQ value of each beam.

After measurement results of the plurality of beams are obtained, in ascenario, a process of S501 to S505 is performed for each beam, and thecell reselection procedure is triggered only when preset timerscorresponding to all beams expire.

In another scenario, a measurement result of the UE may be firstselected from measurement results of all beams based on the measurementresults of all the beams. For example, a measurement result of anoptimal beam is selected as the measurement result of the UE in eachround of measurement, and then the selected measurement result iscompared with Qin and Qout in step S502, thereby improving accuracy oftriggering the cell reselection procedure.

For ease of description, a measurement result of measuring the servingbeam is used as an example for description with reference to a service,as shown in FIG. 8.

In FIG. 8, UE includes a UE lower layer and a UE higher layer, and theUE lower layer measures channel quality of a beam to obtain ameasurement result such as an RSRP or RSRQ. In addition, the UE lowerlayer compares the measurement result with Qin and Qout. When themeasurement result is lower than Qout, the UE lower layer generates afirst signal such as out of sync, and sends the first signal to the UEhigher layer. When the measurement result is higher than Qin, the UElower layer generates a second signal such as in sync, and sends thesecond signal to the UE higher layer.

When a quantity of times of continuously sending the first signal by theUE lower layer to the UE higher layer exceeds a first preset quantity oftimes, it indicates that channel quality measured in a plurality ofconsecutive preset time periods is lower than the preset unreliabilitythreshold. In this case, the UE higher layer starts a preset timer.After the preset timer is started, if a quantity of times ofcontinuously sending the second signal by the UE lower layer to the UEhigher layer exceeds a second preset quantity of times, it indicatesthat channel quality measured in a plurality of consecutive preset timeperiods is higher than the preset reliability threshold. In this case,the UE higher layer terminates the preset timer. Timing duration of thepreset timer is T.

After the preset timer is started, if a quantity of times ofcontinuously sending the second signal by the UE lower layer to the UEhigher layer does not exceed a second preset quantity of times, thepreset timer expires. In this case, it may be determined that an RLFoccurs, and a cell reselection procedure is triggered.

An embodiment of the present disclosure further provides acommunications apparatus, applied to user equipment, where the userequipment can communicate with the network device by using a pluralityof beams, the plurality of beams include a first beam and at least onesecond beam, the first beam is a serving beam used by the user equipmentto listen to control information, and the second beam is a beam otherthan the serving beam. As shown in FIG. 9, the apparatus includes:

a processing module 91, configured to determine that the serving beam isblocked; and

a receiving module 92, configured to obtain a first message from thenetwork device by using the first beam or the second beam.

FIG. 10 is a schematic structural diagram of an electronic deviceaccording to an embodiment of the present disclosure. In the embodimentof the present disclosure, the processing module 91 may be a processor101 in FIG. 10, and the receiving module 92 may be a receiver 102 inFIG. 10.

Optionally, in an embodiment of the present disclosure, as shown in FIG.9, the apparatus further includes:

a sending module 93, configured to send a response message in responseto the first message, where the response message is used to indicate abeam used by the receiving module to obtain the first message.

In the embodiment of the present disclosure, the sending module 93 maybe a transmitter 103 in FIG. 10.

Optionally, in another embodiment of the present disclosure, thereceiving module 91 is further configured to obtain a beam switchingmessage that is sent by the network device in response to the responsemessage, where the beam switching message is used to indicate that oneof the plurality of beams is a next serving beam of the user equipment.

In still another embodiment of the present disclosure, the sendingmodule 93 is further configured to send a blocking message by using apreset uplink resource, where the blocking message is used to instructthe network device to send the first message in response to the blockingmessage.

Optionally, in still another embodiment of the present disclosure, thesecond beam includes a plurality of beams.

Optionally, in still another embodiment of the present disclosure, thatthe receiving module 92 is configured to obtain a first message from thenetwork device by using the first beam or the second beam isspecifically:

the receiving module 92 is configured to receive, on the first beam andeach second beam, the first message sent by the network device; or

the receiving module 92 is configured to: search for all beams in apreset beam combination, where the preset beam combination includes thefirst beam, or the first beam and any quantity of second beams; andreceive the first message that is sent by the network device by usingany one or more beams in the preset beam combination; or

the receiving module 92 is configured to: select, at different timepoints by using a preconfigured correspondence between a beam and a timepoint, a corresponding single beam from the first beam and all secondbeams for performing a search; and receive the first message that issent by the network device by using the selected single beam; or

the receiving module 92 is configured to: search for all the beams inthe preset beam combination; when the first message is received on noneof the beams in the preset beam combination, select, at different timepoints by using a preconfigured correspondence between a beam and a timepoint, a corresponding single beam from a beam outside the preset beamcombination for performing a search; and receive the first message thatis sent by the network device by using the selected single beam.

Optionally, in still another embodiment of the present disclosure, thefirst message carries one piece or a combination of indicationinformation and data information.

Optionally, in still another embodiment of the present disclosure, theindication information is a PDCCH order.

The processing module 91 is further configured to generate a preamble inresponse to the PDCCH order.

That the sending module 93 is configured to send a response message inresponse to the first message is specifically:

the sending module 93 is configured to send the preamble on a presetrandom access resource in a beam used by the first message; or

the sending module 93 is configured to send the preamble on a presetrandom access resource in all beams used by the first message; or

the sending module 93 is configured to: determine a beam with a greatestsignal power in all beams used by the first message, and send thepreamble on a preset random access resource in the beam with thegreatest power; or

the sending module 93 is configured to: after sending the preamble on apreset random access resource in a beam on which the first message isreceived, receive the first message from another beam, and if a signalpower of the another beam is greater than a signal power of the previousbeam, send the preamble on a preset random access resource in theanother beam.

Optionally, in still another embodiment of the present disclosure, theindication information is uplink scheduling indication information.

The processing module 91 is further configured to determine ameasurement report that includes communication quality of all beams.

That the sending module 93 is configured to send a response message inresponse to the first message is specifically:

the sending module 93 is configured to send the measurement report byusing a preset time-frequency resource in any beam used by the firstmessage.

Optionally, in still another embodiment of the present disclosure, theprocessing module 93 is further configured to: measure channel qualityof at least one of the plurality of beams in a plurality of consecutivepreset time periods in response to the blocking of the serving beam;

separately compare a channel quality value in each time period with apreset reliability threshold and a preset unreliability threshold, wherethe preset reliability threshold is greater than the presetunreliability threshold; and

if channel quality measured in each of the plurality of consecutivepreset time periods is lower than the preset unreliability threshold,start a preset timer; or if channel quality measured in each of theplurality of consecutive preset time periods after the preset timer isstarted is higher than the preset reliability threshold, terminate thepreset timer; or if channel quality measured in none of the plurality ofconsecutive preset time periods after the preset timer is started ishigher than the preset reliability threshold, and the preset timerexpires, trigger a cell reselection procedure.

An embodiment of the present disclosure further provides acommunications apparatus, applied to a network device, where userequipment can communicate with the network device by using a pluralityof beams, the plurality of beams include a first beam and at least onesecond beam, the first beam is a serving beam used by the user equipmentto listen to control information, and the second beam is a beam otherthan the serving beam. As shown in FIG. 11, the apparatus includes:

the processing module 111, configured to determine that the serving beamis blocked; and

the sending module 112, configured to send a first message by using thefirst beam or the second beam.

FIG. 12 is a schematic structural diagram of an electronic deviceaccording to an embodiment of the present disclosure. In the embodimentof the present disclosure, the processing module 111 may be a processor121 in FIG. 12, and the receiving module 112 may be a receiver 122 inFIG. 12.

Optionally, in another embodiment of the present disclosure, as shown inFIG. 11, the apparatus further includes a receiving module 113.

That the processing module 111 is configured to determine that theserving beam is blocked is specifically:

if the receiving module 113 does not receive, within preset durationafter the network device sends a second message, a feedback message thatis sent by the user equipment in response to the second message, theprocessing module 111 is configured to determine that the serving beamis blocked; or

if the receiving module 113 receives a blocking message that is sent bythe user equipment by using the first beam or the second beam, theprocessing module 111 is configured to determine that the serving beamis blocked.

In the embodiment of the present disclosure, the sending module 113 maybe a transmitter 123 in FIG. 12.

Optionally, in still another embodiment of the present disclosure, thereceiving module 112 is further configured to obtain a response messagethat is sent by the user equipment in response to the first message,where the response message is used to indicate a beam used by the userequipment to obtain the first message.

The sending module 113 is further configured to send, by the networkdevice, a beam switching message in response to the response message,where the beam switching message is used to indicate that one of theplurality of beams is a next serving beam of the user equipment.

Optionally, in still another embodiment of the present disclosure, thesecond beam includes a plurality of beams.

In still another embodiment of the present disclosure, that the sendingmodule 113 is configured to send a first message by using the first beamor the second beam is specifically:

the sending module 113 is configured to send the first message by usingthe first beam and each second beam; or

the sending module 113 is configured to send the first message by usingall beams in a preset beam combination, where the preset beamcombination includes the first beam, or the first beam and any quantityof second beams; or

the sending module 113 is configured to: select a corresponding singlebeam from the first beam and all second beams at different time pointsby using a preconfigured correspondence between a beam and a time point;and send the first message by using the selected single beam; or

the sending module 113 is configured to: send the first message by usingall the beams in the preset beam combination; if the response messagethat is sent by the user equipment in response to the first message isreceived on none of the beams in the preset beam combination, select acorresponding single beam from the plurality of beams or a beam outsidethe preset beam combination at different time points by using apreconfigured correspondence between a beam and a time point; and sendthe first message by using the selected single beam.

Optionally, in still another embodiment of the present disclosure, thefirst message carries one piece or a combination of indicationinformation and data information.

In still another embodiment of the present disclosure, the indicationinformation is a PDCCH order.

That the receiving module 112 is configured to obtain a response messagethat is sent by the user equipment in response to the first message isspecifically:

the receiving module 112 is configured to receive a preamble that issent by the user equipment by using one or more beams.

Optionally, in still another embodiment of the present disclosure, theprocessing module 111 is further configured to: if the preamble isreceived by using one beam, determine, as a next serving beam, the beamused by the preamble; or if the preamble is received by using at leasttwo beams, determine a beam with a greatest signal power in the at leasttwo beams as a next serving beam; or if the preamble is received byusing at least two beams, determine, as a next serving beam, a beam usedby a last received preamble.

That the sending module 113 is configured to send a beam switchingmessage in response to the response message is specifically:

the sending module 113 is configured to send identification informationof the next serving beam in response to the response message.

Optionally, in still another embodiment of the present disclosure, theindication information is uplink scheduling indication information.

That the receiving module 112 is configured to obtain a response messagethat is sent by the user equipment in response to the first message isspecifically:

the receiving module 112 is configured to receive a measurement reportthat is of all of the plurality of beams and that is sent by using onebeam.

Optionally, in still another embodiment of the present disclosure, theprocessing module 111 is further configured to determine, as a nextserving beam, a beam with a greatest signal power in all of theplurality of beams in response to the measurement report.

That the sending module 113 is configured to send a beam switchingmessage in response to the response message is specifically:

the sending module 113 is configured to send identification informationof the next serving beam in response to the response message.

An embodiment of the present disclosure further provides acommunications system, and the communications system may include theuser equipment shown in FIG. 10 and the network device shown in FIG. 12.

The described apparatus embodiments are merely examples. The unitsdescribed as separate parts may or may not be physically separate, andparts displayed as units may or may not be physical units, may belocated in one position, or may be distributed on a plurality of networkunits. Some or all of the modules may be selected according to actualneeds to achieve the objectives of the solutions of the embodiments.

Based on the foregoing descriptions of the embodiments, a person skilledin the art may clearly understand that the embodiments may beimplemented by software in addition to a universal hardware platform orby hardware only. Based on such an understanding, the technicalsolutions essentially or the part contributing to the related art may beimplemented in a form of a software product. The computer softwareproduct may be stored in a computer-readable storage medium, such as aROM/RAM, a magnetic disk, or an optical disc, and includes severalinstructions for instructing a computer device (which may be a personalcomputer, a server, a network device, or the like) to perform themethods described in the embodiments or some parts of the embodiments.

A person skilled in the art can easily figure out another implementationsolution of the present disclosure after considering the specificationand practicing the present disclosure disclosed herein. This applicationis intended to cover any variations, functions, or adaptive changes ofthe present disclosure. These variations, functions, or adaptive changescomply with general principles of the present disclosure, and includecommon knowledge or a commonly used technical means in the technicalfield that is not disclosed in the present disclosure. The specificationand the embodiments are merely considered as examples, and the actualscope and the spirit of the present disclosure are pointed out by theappended claims.

It should be understood that the present disclosure is not limited tothe accurate structures that are described in the foregoing and that areshown in the accompanying drawings, and modifications and changes may bemade without departing from the scope of the present disclosure. Thescope of the present disclosure is limited only by the appended claims.

What is claimed is:
 1. A communication method, wherein user equipment isconfigured to communicate with a network device by using a plurality ofbeams, wherein the plurality of beams comprise a first beam and at leastone second beam, the first beam is a serving beam for use by the userequipment to listen to control information, and the second beam is abeam other than the serving beam, the method comprising: determining, bythe user equipment, that the serving beam is blocked; obtaining, by theuser equipment, a first message from the network device by using thefirst beam or the second beam; sending, by the user equipment, aresponse message in response to the first message for indicating a beamused by the user equipment to obtain the first message; and obtaining,by the user equipment, a beam switching message sent by the networkdevice in response to the response message, wherein the beam switchingmessage indicates that one of the plurality of beams is a next servingbeam of the user equipment.
 2. The method according to claim 1, furthercomprising: sending, by the user equipment, a blocking message by usinga preset uplink resource for instructing the network device to send thefirst message in response to the blocking message.
 3. The methodaccording to claim 1, wherein the second beam comprises a plurality ofbeams.
 4. The method according to claim 3, wherein obtaining, by theuser equipment, a first message from the network device by using thefirst beam or the second beam comprises: receiving, by the userequipment on the first beam and each second beam, the first message sentby the network device; or searching, by the user equipment, for allbeams in a preset beam combination, wherein the preset beam combinationcomprises: the first beam, or the first beam and any quantity of secondbeams, and receiving the first message sent by the network device byusing any one or more beams in the preset beam combination; orselecting, by the user equipment at different time points by using apreconfigured correspondence between a beam and a time point, acorresponding single beam from the first beam and all second beams forperforming a search, and receiving the first message sent by the networkdevice by using the selected single beam; or searching, by the userequipment, for all the beams in the preset beam combination, when thefirst message is received on none of the beams in the preset beamcombination, selecting, at different time points by using apreconfigured correspondence between a beam and a time point, acorresponding single beam from the plurality of beams or a beam outsidethe preset beam combination for performing a search, and receiving thefirst message that is sent by the network device by using the selectedsingle beam.
 5. The method according to claim 1, wherein the firstmessage comprises one piece or a combination of indication informationand data information.
 6. The method according to claim 5, wherein: theindication information is a physical downlink control channel (PDCCH)order; the method further comprises: in response to the PDCCH order,generating, by the user equipment, a preamble; and sending, by the userequipment, a response message in response to the first messagecomprises: sending, by the user equipment, the preamble on a presetrandom access resource in a beam used by the first message, or sending,by the user equipment, the preamble on a preset random access resourcein all beams used by the first message, or determining, by the userequipment, a beam with a greatest communication quality value in allbeams used by the first message, and sending the preamble on a presetrandom access resource in the determined beam, or after sending thepreamble on a preset random access resource in a beam on which the firstmessage is received, receiving, by the user equipment, the first messagefrom another beam, and when a communication quality value of the anotherbeam is greater than a communication quality value of the previous beam,sending the preamble on a preset random access resource in the anotherbeam.
 7. The method according to claim 5, wherein: the indicationinformation is uplink scheduling indication information; the methodfurther comprises: determining, by the user equipment, a measurementreport that comprises communication quality of all beams; and sending,by the user equipment, a response message in response to the firstmessage comprises: sending, by the user equipment, the measurementreport by using a preset time-frequency resource in any beam used by thefirst message.
 8. The method according to claim 1, further comprising:measuring, by the user equipment, channel quality of at least one of theplurality of beams in a plurality of consecutive preset time periods inresponse to the blocking of the serving beam; separately comparing, bythe user equipment, a channel quality value in each time period with apreset reliability threshold and a preset unreliability threshold,wherein the preset reliability threshold is greater than the presetunreliability threshold; and when the channel quality measured in eachof the plurality of consecutive preset time periods is lower than thepreset unreliability threshold, starting, by the user equipment, apreset timer; or when the channel quality measured in each of theplurality of consecutive preset time periods after the preset timer isstarted is higher than the preset reliability threshold, terminating, bythe user equipment, the preset timer; or when the channel qualitymeasured in each of the plurality of consecutive preset time periodsafter the preset timer is started is higher than the preset reliabilitythreshold, and the preset timer expires, triggering, by the userequipment, a cell reselection procedure.
 9. User equipment configured tocommunicate with a network device by using a plurality of beams, whereinthe plurality of beams comprise a first beam and at least one secondbeam, the first beam is a serving beam used by the user equipment tolisten to control information, and the second beam is a beam other thanthe serving beam, the user equipment comprising: a processor configuredto determine that the serving beam is blocked; a receiver configured toobtain a first message from the network device by using the first beamor the second beam; and a transmitter configured to send a responsemessage in response to the first message for indicating a beam used bythe receiver to obtain the first message; and, wherein the receiver isfurther configured to: obtain a beam switching message that is sent bythe network device in response to the response message, wherein the beamswitching message indicates that one of the plurality of beams is a nextserving beam of the user equipment.
 10. The user equipment according toclaim 9, wherein the transmitter is further configured to: send ablocking message by using a preset uplink resource for instructing thenetwork device to send the first message in response to the blockingmessage.
 11. The user equipment according to claim 9, wherein the secondbeam comprises a plurality of beams.
 12. The user equipment according toclaim 11, wherein to obtain a first message from the network device byusing the first beam or the second beam, the receiver is configured to:receive, on the first beam and each second beam, the first message sentby the network device; or search for all beams in a preset beamcombination, wherein the preset beam combination comprises the firstbeam, or the first beam and any quantity of second beams, and receivethe first message that is sent by the network device by using any one ormore beams in the preset beam combination; or select, at different timepoints by using a preconfigured correspondence between a beam and a timepoint, a corresponding single beam from the first beam and all secondbeams for performing a search, and receive the first message that issent by the network device by using the selected single beam; or searchfor all the beams in the preset beam combination, and when the firstmessage is received on none of the beams in the preset beam combination,select, at different time points by using a preconfigured correspondencebetween a beam and a time point, a corresponding single beam from a beamoutside the preset beam combination for performing a search, and receivethe first message that is sent by the network device by using theselected single beam.
 13. The user equipment according to claim 9,wherein the first message comprises one piece or a combination ofindication information and data information.
 14. The user equipmentaccording to claim 13, wherein: the indication information is a physicaldownlink control channel (PDCCH) order; the processor is furtherconfigured to generate a preamble in response to the PDCCH order; and tosend a response message in response to the first message, thetransmitter is configured to: send the preamble on a preset randomaccess resource in a beam used by the first message, or send thepreamble on a preset random access resource in all beams used by thefirst message, or determine a beam with a greatest signal power in allbeams used by the first message, and send the preamble on a presetrandom access resource in the beam with the greatest power, or aftersending the preamble on a preset random access resource in a beam onwhich the first message is received, receive the first message fromanother beam, and when a signal power of the another beam is greaterthan a signal power of the previous beam, send the preamble on a presetrandom access resource in the another beam.
 15. The apparatus accordingto claim 13, wherein: the indication information is uplink schedulingindication information; the processor is further configured to determinea measurement report that comprises communication quality of all beams;and to send a response message in response to the first message, thetransmitter is configured to: send the measurement report by using apreset time-frequency resource in any beam used by the first message.16. A system for use in a communications network, the system comprising:user equipment configured to communicate within the communicationsnetwork by using a plurality of beams, wherein the plurality of beamscomprise a first beam and at least one second beam, the first beam is aserving beam used by the user equipment to listen to controlinformation, the second beam is a beam other than the serving beam, andthe user equipment comprises: a processor configured to determine thatthe serving beam is blocked, and a receiver configured to obtain a firstmessage by using the first beam or the second beam; and a networkdevice, comprising, a processor configured to determine that the servingbeam is blocked, and a transmitter configured to send the first messageto the user equipment by using the first beam or the second beam; and,wherein the User Equipment is further configured to: send a responsemessage in response to the first message for indicating a beam used bythe user equipment to obtain the first message; and obtain a beamswitching message sent by the network device in response to the responsemessage, wherein the beam switching message indicates that one of theplurality of beams is a next serving beam of the user equipment.